$Λ$CDM in a courtroom

Ofer Lahav; Paul Shah

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arXiv · 2609.16097

$Λ$CDM in a courtroom

Ofer Lahav·Paul Shah

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Abstract

The cosmological constant $Λ$, and its generalization as Dark Energy, makes up roughly 70% of the present-epoch universe and has been part of the dominant $Λ$CDM cosmological paradigm for more than a quarter of a century. It has been put on trial by recent measurements of galaxy clustering, Type Ia supernovae, and the cosmic microwave background. In this Perspective we evaluate the strength of the evidence for a constant $Λ$, versus Dynamical Dark Energy (DDE) in the light of recent developments. We also assess what the future holds both for our Universe and our understanding of its most mysterious component.

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Ofer Lahav, Paul Shah. 2026-09-14. $Λ$CDM in a courtroom. https://arxiv.org/abs/2609.16097

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